1. Field of the Invention
The present invention relates to a cutting-and-transferring system for cutting and separating a workpiece into individual pellets and for loading carrier trays with such pellets, and to a pellet transferring apparatus for transferring pellets from the cutting apparatus to carrier trays.
2. Related Arts
Recently chip size packages (abbreviated as xe2x80x9cCSPsxe2x80x9d) have been widely used. A plurality of semiconductor chips each having LSIs built therein are arranged, and resin-sealed together to form a CSP substrate, and then the CSP substrate is cut into packaged pellets, each being as large as the original semiconductor chip. Advantageously the CSP device is small in size, requiring a minimum space for installation in personal computers, cellular phones and the like.
Referring to FIG. 11, a cutting apparatus 300 is used in cutting CSP substrates 301. A plurality of carrier frames each having a CSP substrate attached thereon by an adhesive tape T are stacked on each other to be stored in a cassette 302.
The CSP substrate 301 is transferred from the cassette 302 to the tentative storage area 304, where the CSP substrate 301 is sucked and held by the first transferring means 305. Then, the first transferring means 305 turns to bring the CSP substrate 301 to the chuck table 306. The CSP substrate 301 is laid on the chuck table 306 to be sucked and held thereon.
Then, the chuck table 306 is moved in the X-axial direction to be put just under the alignment means 307. A picture of the CSP substrate 301 is taken there to determine where a required cutting may be effected on the CSP substrate 301, and the rotary blade 308 is aligned to a selected cutting line traversing the Y-axis on the CSP substrate 301. Then, the chuck table 306 is moved in the X-axial direction, allowing the rotary blade 308 to cut the CSP substrate 301. This is repeated as many times as the cutting lines running in X-axial directions. After finishing the cutting along each and every cutting line running in the X-axial direction, the chuck table 306 turns 90 degrees, so that the crosswise cutting is repeated, so that the CSP substrate is separated into square pellets.
These pellets are still held on the frame F with the adhesive tape T, and the so cut and separated CSP substrate is transferred to the washing means 311 by the second transferring means 310. The cut and separated CSP substrate is washed there to remove debris, and then the pellets are dried by air blowing.
After the cut and separated CSP substrate is dried, the first transferring means 305 transfer it to the tentative storage area 304, where the taking-in and -out means pushes the separated CSP substrate in a selected slot in the cassette 302. The sequential steps are repeated for each and every CSP substrate so that the frames F each bearing pellets in order are stacked in the cassette 302. Then, the cassette 302 is transported to a selected transferring apparatus in which individual pellets are transferred to carrier trays.
The subsequent pellet-transferring work cannot start before all cut CSP substrates have been put in another cassette 302. Therefore, all units in the transferring apparatus are dormant for the while. Accordingly the yielding rate is lowered. Still disadvantageously, a tedious work is required in removing the cassette 302 from the cutting apparatus 300 and carrying it to the transferring station.
Therefore, there has been an increasing demand for reducing tedious works and for improving the efficiency with which a series of steps may be performed, starting from the cutting of workpieces such as CSPs and ending with the loading of carrier trays with separate pieces such as pellets.
To meet such a demand a cutting-and-transferring system for cutting and separating a workpiece into pellets and for transferring such pellets to carrier trays according to the present invention comprises: a holding table for holding a workpiece to be cut, the workpiece being retained by a holder member; a cutting unit including at least cutting means for cutting the workpiece on the holding table into pellets; a transferring unit including at least transferring means for picking up the pellets from the holder member and for transferring to a selected carrier tray; and a shuttle transfer unit for transferring a selected cut workpiece from the cutting unit to the transferring unit.
The shuttle transfer unit may be built in the transferring unit.
The cutting unit may comprise: a cassette storage area for storing a cassette containing a stack of workpieces; a carrying means for removing a selected workpiece from the cassette; a tentative storage area in which the workpiece thus removed and transferred is laid; a first transferring means for transferring the workpiece from the tentative area to the holding table; an alignment means for detecting the cutting area of the workpiece on the holding table; a cutting means for cutting the so detected cutting area of the workpiece; a washing means for washing the cut workpiece; a second transferring means for transferring the cut workpiece from the holding table to the washing means; a third transferring means for transferring the cut workpiece from the washing means to the tentative storage area; and a fourth transferring means for transferring the cut workpiece from the tentative storage area to a boarding area where the cut workpiece is picked up to be transferred from the cutting unit to the transferring unit; and the transferring unit comprises: a shuttle transferring means for picking up the cut workpiece in the bordering area; a tentative storage means in which the cut workpiece is released from the shuttle-transferring means to be tentatively laid there; a transfer means for transferring the cut workpiece from the tentative storage means to a pick-up table where the cut workpiece is laid to allow the pellets to be picked-up; a pellet transferring means for picking up pellets from the pick-up table to a selected carrier tray; a disposal means for disposing the holder members from which pellets have been removed by the pellet transferring means; an empty-tray storage means for storing empty trays; a loaded-tray storage means for storing trays loaded with pellets; and a tray-transferring table for transferring a selected empty tray from the empty-tray storage means to the pellet transferring means and for transferring a pellet-loaded tray to the loaded-tray storage means.
The pellet transferring means may comprise: a pellet orienting means; a first pick-up means for picking up pellets from the pick-up table to put the pellet thus picked up on the pellet orienting means; and a second pick-up means for picking up and transferring the oriented pellet from the pellet orienting means to a selected carrier tray.
The cutting-and-transporting system may further comprise an additional transferring unit, which is placed to adjoin the transferring unit so that a selected cut workpiece may be transferred to the shuttle transferring means of the subsequent transferring unit via the tentative storage means.
The cutting-and-transferring system may further comprise an ultraviolet radiator means placed in the boarding area, thereby permitting a selected cut workpiece to be exposed to ultraviolet rays when transferred from the tentative storage area to the boarding area, thus lowering the adhesive capability of the holder member of ultraviolet-sensitive adhesive tape.
With the above described arrangement the cutting of a selected workpiece is directly followed by the transporting of the cut workpiece to the transferring unit, thereby permitting the loading of a selected carrier tray with pellets. The cutting-to-transferring continuity makes it unnecessary for the transferring unit to wait a relatively long time for arrival of a cassette containing cut workpieces therein.
A pellet transferring apparatus according to the present invention comprises: a shuttle transferring means for picking up a selected cut workpiece from the cutting unit; a tentative storage means in which the cut workpiece is released from the shuttle transferring means; a transfer means for transferring the cut workpiece to a pick-up table where the cut workpiece is laid to allow the pellets to be removed and picked up; a pellet transferring means for picking up pellets from the pick-up table to a selected carrier tray; a disposal means for disposing the holder members from which pellets have been removed by the pellet transferring means; an empty-tray storage means for storing empty trays; a loaded-tray storage means for storing trays loaded with pellets; and a tray transferring table 76 for transferring empty trays from the empty-tray storage means to the pellet transferring means and for transferring pellet-loaded trays to the loaded-tray storage means.
The pellet transferring means may comprise: a pellet orienting means; a first pick-up means for picking up pellets one after another from the cut workpiece on the pick-up table to put the pellet thus picked up on the pellet orienting means; and a second pick-up means for picking up and transferring the oriented pellet from the pellet orienting means to a selected carrier tray.
The pellet transferring apparatus may further comprise an additional transferring apparatus, which is placed to adjoin the leading transferring apparatus so that a selected cut workpiece may be transferred to the shuttle transferring means of the subsequent transferring unit via the tentative storage means.
An existing cutting apparatus can have the same capability as the cutting-and-transferring system simply by combining it with the pellet transporting apparatus as described above.
Other objects and advantages of the present invention will be understood from the following description of cutting-and-transferring systems and transferring apparatuses according to preferred embodiments of the present invention, which are shown in accompanying drawings.